Section 1 Lecture 1- Origins of Life Life probably started by Hydrothermal Vents. Photosynthesis originated around 3GA, as cells figured out how to fix CO2 and release O2. Eukaryotes originates 1.5-2.5 Ga. Endosymbiosis event occurred between archea and bacteria, like phagocytosis. Engulfed bacteria became mitochondria. Lecture 2- The Study of Life Deductive reasoning uses general principles to make specific predictions, based on reason and logical analysis. Inductive reasoning uses specific observations to develop general conclusions. Uses instinct over reasoning. Lecture 3- Chemicals of Life Water Water has both cohesive properties, meaning it can stick together, and adhesive properties, meaning it can stick to other particles or surfaces. Hydrophobic & Hydrophilic Hydrophobic substances fear or repel water. Hydrophilic substances are polar molecules. They can transiently bond with water. Lecture 4-6 Macromolecules carbon, carbohydrates and lipids Hydrocarbons Formed by a carbon chain skeleton. They are organic molecules that only contain carbon and hydrogen. Hydrocarbons are present in almost all
molecules in biological organisms. The properties of hydrocarbons are determined by the carbon skeleton structure and the functional groups. Functional Groups Functional groups can change properties of hydrocarbons, e.g. make It hydrophilic. Monomer/Polymer/Linkage Monomer-Monosaccharide Polymer- Polysaccharide Linkage- Glycolytic Condensation/Hydrolysis Condensation/Dehydration reactions lose water- they form an external water molecule. These reactions synthesize macromolecules. Hydrolysis reactions incorporate water. Polysaccharides are hydrolyzed when blood sugar levels are low. Storage and Structural Polysaccharides Storage polysaccharides in plants are starch and in animals it s glycogen, both in the form of alpha-glucose. Structural polysaccharides include
cellulose in plants and chitin, the exoskeleton in arthropods, in the form of beta-glucose. Lipids Lipids are the smallest of the macromolecules. They are made up of hydrocarbons and are mainly non-polar bonds. They have little or no affinity for water, making them hydrophobic. Monomer/Polymer/Linkage Monomer: Fatty Acid Polymer: Triglyceride Linkage: Ester Linkage Synthesis Fatty Acids are long chain hydrocarbons-16-18 carbons with a carboxyl group at one end. These link with a Glycerol, 3 Carbons and 3 Hydroxyl
Groups, via a dehydration reaction to synthesize triglycerides with an ester linkage. Saturated vs Unsaturated Fatty Acids Fatty acids are either saturated or unsaturated. Saturated Fas are saturated with hydrogen and contain single covalent bonds. Unsaturated FA s contain one or more double covalent bonds. Saturated fatty acids are straight: whilst unsaturated fatty acids are kinked and prevented from packing closely together: Phospholipids Similar to triacylglycerol, phospholipids have a glycerol, but only 2 fatty acid tails. They also have a phosphate functional group, making them
amphipathic, as the phosphate is hydrophilic and the fatty acid is hydrophobic. Phospholipids organize themselves so that the polar head is facing the outside of the membrane, and the non-polar hydrophobic tail is inside. Lipids are essential to make cell membranes. Lecture 7-8 Macromolecules- Proteins and Enzymes Monomer/Polymer/Linkage Monomer: Amino Acid Polymer: Polypeptide Linkage: Peptide bond Structure Amino Acids have an Amino Group, an R-group and a Carboxyl Group. The properties of an amino acid are determined by the R-Group.
Polar amino acids (uncharged) usually have oxygen in their R-groups. Peptide bonds involve a link between the last COOH on one amino acid and the NH3 on the other. The polypeptide grows at the C-terminus. Conformation Primary Structure Includes unique AA sequences. N terminus to C terminus direction. Tells us nothing about 3D structure of configuration. Secondary Structure First Folding, forms a-helix or B-pleated sheets. Tertiary Structure Arrangement of a-helices and B-pleated sheets. Involves interactions of R-groups and amino acids. *Quaternary Structure* Only some polypeptides cannot function without an adjacent polypeptide, e.g. hemoglobin.